Inquisitor gets more flat with one Havoc and Unchained Grasp. Soldier and Inquisitor both get 150%-200% more physical damage easily, so whatever flat you get from Necro won’t mean as much. The only real advantage is another WPS, and Oppressor with 2 Deathdealers is completely starved for skill points, since it gives you all of 4 points per gun.
Genuine question, what elemental to phys gear would you expect to use on an oppressor that’ll also support RF and leave you with enough skill points? Because just converting vit and half of aether will still output lower total damage without any %phys.